2003 70 HP Johnson / Suzuki running rich

[Lake Toho]

I have a 2003 70 HP Johnson / Suzuki that is running rich. I've had the injectors checked and have changed the spark plugs. No change. Is there an electric fuel module that may be causing the problem? If so where is it located?

 

[racerone]

How did you determine it is running " rich"?---What is your motor doing / not doing?----What trouble shooting has been done ?

 

[Lake Toho]

Thanks for answering my post.
Spark plugs are very dark, almost black. Runs rough at an idle. Exhaust has a lot of fuel in in it. Can see it in the water.

 

[airshot]

You have some testing to do....how old are the fuel hoses? What is the compression on each cylinder ?
When was the last time the carbs were rebuilt ? How good is the fuel ? How much of a gap will each plug wire jump ? Need info before we can guess !!

 

[racerone]

???----This motor does not have carburetors at all !!!---

 

[Lake Toho]

Fuel hose are older. Compression is good in all 4 cylinders. No carbs, fuel injected. Fuel is new. Spark jumps about a 1/4". I had the engine gone through last summer and everything checked out good. This burning rich happened all at once. That's why I thought it may be electrical. I was also told the high pressure Fuel pump my be picking up crankcase pressure and making it pump more fuel then it should.
Thanks for the quick responses

 

[racerone]

The high pressure fuel pump is inside the vapour seperator tank.----It is an electric pump.-----I doubt it is picking up crankcase pressure from this 4 stroke motor !-----Who told you this story about the high pressure pump ?

 

[Lake Toho]

A guy working on a neighbors boat. I didn't think it carried much weight.

 

[oldboat1]

Sometimes solvents are appropriate. Your fuel injectors may need to be cleaned. Check your manual, search the internet, etc. Don't simply dump a solvent in your fuel tank -- risks moving debris from the tank to the engine. After using an appropriate injector cleaning method, replace all filters and start with fresh fuel -- from a clean tank.

 

[Crosbyman]

your 20 year old fuel injected engine much like etecs requires CLEAN fuel and anything affecting or HAVING AFFECTED the fuel distribution will mess up the injectors, VST filters HS pump
(etecs have filters in the HS pump)

the fuel lines are likely original and may have started crumbling with specs of rubber reacing the injectors preventing them from properly closing off the fuel supply to the sparkplugs.

I believe there are some tests that can be done to confirm injector pressure retention... if the injectors can't hold a given pressure they will "leak" extra fuel .

conclusion .... cleaning injectors is likely overdue as well as replacement of all fuel carrying hoses

 

[airshot]

???----This motor does not have carburetors at all !!!---

Sorry just citing general questions and tests to get an insite as to the motors condition.

 

[racerone]

Post #1 says that injectors were checked.-------Inspection / cleaning of VST should be done.------Thermostat and water pump maintained ?

 

[Crosbyman]

dont know what "checked " means unless it was a full clean-up
see video of what can happen

 

[Crosbyman]

part 2 and typical pressure tests

 

[racerone]

This motor is a SUZUKI 4 stroke.

 

[Crosbyman]

does it have injectors like a ETEC used as example.... in the videos to show what dirty injectors can do to performance ?

suzuki specific videos available on utube showing injector, vst and filter maintenance

your 20 year old fuel injected engine much like etecs.....

 

[Lake Toho]

Sometimes solvents are appropriate. Your fuel injectors may need to be cleaned. Check your manual, search the internet, etc. Don't simply dump a solvent in your fuel tank -- risks moving debris from the tank to the engine. After using an appropriate injector cleaning method, replace all filters and start with fresh fuel -- from a clean fuel tank

I'll give that a try. Thanks